The relationship between mRNA methylation and processing will be examined using several systems. Inhibitors of mRNA methylation will be used to block methylation in cultured cells at specific sites in the messenger RNA molecule. Analysis of undermethylated mRNA generated in the presence of these inhibitors will be used to assess the requirement of methylation for nuclear transport and translation on polysomes. An in vitro nuclear transport system will be used to further study the nature of the released mRNA molecules. A specific eukaryotic mRNA, prolactin mRNA, will be purified from bovine pituitary tissue. Complementary DNA will be synthesized by reverse transcriptase and used to isolate nuclear and cytoplasmic prolactin mRNA sequences for further physical and chemical characterization.